OBJECTIVE Our purpose was to evaluate the incidence and patterns of chromosomal abnormalities in fetuses with absent end-diastolic velocity in umbilical artery and to analyze maternal and fetal factors associated with abnormal karyotype. METHODS One hundred ninety-two fetuses of known karyotype with absent end-diastolic velocity in the umbilical artery at a gestational age > 20 weeks were considered. The following potential risk factors were analyzed in a multiple logistic regression model: maternal age, gravidity, parity, gestational age at diagnosis, presence of gestational hypertension and preeclampsia, presence of fetal malformations, different biometric measurements, head/abdominal circumference ratio, amniotic fluid volume, and several Doppler index values calculated from uterine arteries, fetal heart, and fetal peripheral arteries and veins. RESULTS Sixteen cases had an abnormal karyotype. In two cases a triploidy was present, whereas the remaining 14 cases had autosomal aberrations. The risk factors statistically significantly and independently associated with the presence of an abnormal karyotype were maternal age > 35 years, gestational age at diagnosis < 27 weeks, presence of multiple malformations, and absence of gestational hypertension and preeclampsia. All the fetuses with an abnormal karyotype but one were correctly identified by at least one risk factor. CONCLUSIONS An abnormal karyotype is present in 8.3% of fetuses with absent end-diastolic velocity in umbilical artery and is associated with maternal and fetal risk factors. The knowledge of these factors may be useful in the management of such fetuses.